Operation of medical monitors is an issue of major importance. In most cases, such monitors are operated by personnel without technical education, such as nurses. The increasing complexity of state-of-the-art medical monitors, and the additional functionality provided by such equipment, as compared to prior art monitors, makes it necessary to focus on an easy-to-operate "man-machine" interface. In the field of medical monitoring, this is a particularly important problem, not only due to the time it takes to train a non-technical person, but also for reasons of patient safety. For example, if a nurse accidentally switches off the alarm capability of a medical monitor, this may well lead to the death of the patient.
There have already been attempts in the prior art to overcome the restrictions of the "knob and button" approach. For example, buttons not required for everyday operation of a monitor have been hidden behind a cover. Likewise, operation of the monitors has been automated, in order to reduce the amount of human interactions.
Another approach is the use of softkeys, i.e., keys without a fixed label, and with dynamically assigned function. One successful attempt to implement such a softkey concept in a medical monitor is disclosed in U.S. Pat. No. 5,056,059. This prior art human interface uses two- or three-level input sequences, wherein the meaning of the softkeys changes from level to level.
However, it will be noted that a softkey concept requires expensive hardware components, like a display (which is used to depict the various softkey labels). Therefore, the softkey approach is useful in applications which require an expensive monitor, and a display anyway (as is the case in the configurable monitor according to U.S. Pat. No. 5,056,059).
In contrast, the softkey concept does not meet the needs of small or stand-alone monitors which are not equipped with a display, and the necessary number of keys. It will be understood that it would be an extremely costly measure to provide a display simply for the purpose of labelling the softkeys.
Another attempt to make the user interface easier relies on menu-driven user interaction. That is, the user is guided through several steps, and the monitor may propose adequate measures. However, such menus require the provision of a display as well.
The above concepts are also not suited for operation by the patient himself, e.g., in home monitoring applications (i.e., a monitor located at the patient's home). Whatever operating concept is used during home monitoring, the patient will have to study complex instructions. In this context, it is particularly important to note that a medical monitor includes a multiplicity of functions which are partially sensitive to patient safety; likewise, the order of the steps is important. Consider, for example, a calibration procedure wherein the sequence of steps has to be performed in the correct order. If this order is not kept, the monitor will be incorrectly calibrated and therefore not indicate a dangerous situation of the patient.
Yet another problem associated with home monitoring is the correct anamnesis. During home monitoring, the vital signs (like the electrocardiogram, respiration, temperature etc.) are usually recorded by a remote monitor and transmitted to the hospital, or the doctor's office, via telephone lines. However, home monitoring requires not only that the vital signs of the patient are picked up by various transducers, but also some additional information which cannot be measured by a medical monitor, such as general feeling, skin color, weight etc. In the prior art, this additional information has been communicated over the phone. A person at the receiving end (doctor, nurse) recorded the answers and coded them for electronic processing. However, it will be appreciated that this process as such is very labour-intensive, costly and uncomfortable for the patient--a person recording his answers will not always be available, an extra telephone connection has to be set up, and the monitoring cycle is interrupted.
Although it would be possible to use an interactive and/or menu-driven system to record the patient's answers, this solution suffers from the same drawbacks as outlined above. That is, a display is required, the system is error-prone etc.
It is understood that this is not only a problem in home monitoring; in contrast, it applies whenever the patient provides an auto-anamnesis.
The above considerations apply particularly in cases of fetal monitoring with a "home monitor", i.e., when a fetal monitor is used in the pregnant woman's home. The well-being of the mother, pain etc. is clinically important information which cannot be transmitted to the hospital, or the obstetrician's office, in a cost-effective and convenient manner by the equipment provided by prior art solutions.